Changes in hemocytes of Plutella xylostella after parasitism by Diadegma semiclausum.
We examined the changes of hemocytes in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), due to parasitism by the endoparasitoid Diadegma semiclausum (Hymenoptera: Ichneumonidae). Necrosis of prohemocytes in different stages was observed while cell death was absent in the mature hemocytes in the parasitized larvae, which was related to the declined total hemocyte count per microliter (THC). THC in the host hemolymph declined sharply by 12 h post-parasitization and then remained at a low level. When hemocytes of the parasitized larvae were cultured in vitro, encapsulation ability was suppressed coincidently with the inhibited spreading ability; however, such effects were transient. Simultaneously, activation of the prophenoloxidae from the hemocytes was inhibited. Unlike the results of previous studies, the decrease in hemocytes, which was due to the necrosis of the prohemocytes instead of the mature hemocytes in our study, was not responsible for the impaired encapsulation. Our studies suggest that parasitism by D. semiclausum have some effects on hematopoietic regulation and on hemocyte immune reaction of P. xylostella larvae.
Huang
Fang
F
Institute of Insect Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou, China.
Shi
Min
M
Yang
Yan-yan
YY
Li
Jun-ying
JY
Chen
Xue-xin
XX
D000818:Animals; D004156:Catechol Oxidase / Q000097:blood; D016923:Cell Death; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000097:blood; D006434:Hemocytes / Q000201:enzymology; D006790:Host-Parasite Interactions; D006927:Hymenoptera / Q000502:physiology*; D007915:Lepidoptera / Q000469:parasitology*
D004792:Enzyme Precursors; C038451:pro-phenoloxidase; D004156:Catechol Oxidase